This invention relates to a device for insulating parts of the spray liquid supply line, the spray liquid reservoir and the feed pump from the high tension voltage of an electrostatic spray systeem when using an electrically conductive liquid spray material such as a water based paint or a paint containing metallic particles.
In particular, the invention concerns a device of the above type in which a vessel containing a barrier forming liquid is incorporated in the spray liquid supply line as described in European patent application No. 87850083.4.
A problem inherent in the above described device is identified as an uncontrolled tension gradient within the barrier forming liquid such that electrical fields of very high magnitudes are formed, and the spray liquid, which is transported through the barrier forming liquid in drop form, is torn up into a cloud of very small droplets. When disintegrated to such an extent, the spray liquid does not respond to gravitation forces, whereby it is difficult to have the spray liquid transported through the barrier forming liquid by the influence of gravitation.
The above problem is solved by the invention as it is defined in the claims .